Coakley was in Washington for the arguments Wednesday by two of her assistants.

Liberal and conservative justices alike expressed misgivings about the law. The court questioned the size of the zone and asked whether the state could find less restrictive ways of preventing abortion opponents from impeding access to clinics.

Coakley called the questions “insightful” but said she believes the Massachusetts law balances constitutional rights and she’s hopeful the justices will uphold it.

Abortion opponents say the law restricts their free speech and makes it difficult for them to discuss alternatives to abortion with clinic patients.

Coakley said the statute protects public safety and access to health services.